- This narrative review provides evidence-based explanations to some of the common clinical concerns regarding inhaled corticosteroids. Inhaled corticosteroids are the treatment of choice for a newly diagnosed asthmatic patient. Better results are obtained when treatment is initiated as soon as the diagnosis is made. Asthma control can be achieved and maintained in most patients with a low or moderate dose of inhaled corticosteroid administered in two daily doses. Longer duration of treatment provides more sustained benefits than treatment that is intermittent and for short periods of time. The clinical benefits can be observed within 24 hours of commencing treatment and may be more pronounced in patients with an eosinophilic bronchitis. Inhaled corticosteroids provide additional benefit when used in conjunction with prednisone in acute severe asthma. Low doses do not have clinically deleterious side effects on the bones, growth, eye, or hypothalamo-pituitary-adrenal-axis. However, they do not normalize lung function and prevent structural changes in the airway wall in all asthmatic patients.